NO345418B1

NO345418B1 - A fish separator

Info

Publication number: NO345418B1
Application number: NO20190908A
Authority: NO
Inventors: Øyvind Nymark; Frank Øren
Original assignee: Smir As
Priority date: 2019-07-19
Filing date: 2019-07-19
Publication date: 2021-01-25
Also published as: NO20190908A1

Description

Technical Field

The present invention relates to a separator for separating cleaner fish from farmed fish.

Background

A major challenge in the fish farming industry today is the increasing number of sea lice which attack farmed fishes.

An example of such lice are salmon lice which attach themselves to the salmon and causes skin damage. The skin damage makes the salmon more susceptible to infections and illnesses which can lead to death.

It is therefore important to keep the number of sea lice in a controllable amount such that the sea lice do not cause major injury to the farmed fishes.

A number of mechanical devices and chemical methods are known to fight the increasing number of sea lice.

Further, cleaner fish, such as lumpfish and different species of wrasse, are commonly used for controlling the amount of sea lice in the fish farming industry. The cleaner fish is added to the net cage of the farmed fish to remove and eat the sea lice from the farmed fish.

During fish farming the farmer conducts different treatments and/or moves the farmed fishes from one location to another. Before such operations it is often needed to separate the cleaner fish from the farmed fish. The reason for this may for example be that the cleaner fish cannot take the treatment that the farmed fishes will be exposed to.

The anatomy of the lumpfish makes it difficult to separate from the farmed fishes because of its round and sticky body. The devices already known for the purpose of separating lumpfish from farmed fish do not work efficiently enough and therefor the farmer is faced with a time-consuming task of fishing out the lumpfish before the treatment of the farmed fish can start.

NO 334892 B1 discloses a device for moving cleaner fish from farmed fish, wherein the device comprises a trap for enclosing the cleaner fish in pipes of water and thereafter lifting the pipes comprising the cleaner fish out of the water and move it to a desired location.

NO 343535 B1 discloses a device for storage of alive cleaner fish comprising holes adapted for storing the cleaner fish. Further a water reservoir within the device allows the cleaner fishes to be removed to a different location.

NO 341228 B1 discloses a closed system for sorting fish such as cleaner fish from farmed fish. The fish is sent through a pipe into a separator comprising a grid structure/grill wherein the transportation water is drained through the grid structure 3A first, and thereafter the cleaner fish falls through the grid structure 3B. The grid structure is too small for allowing the farmed fish to fall through. Hence, the drained transportation water is drained off, while the cleaner fish is collected into one tank 1 and the farmed fish into another tank (2).

NO 314481 B1 discloses a relatively complex device for a continuous sorting of fish in a closed pipe system which is filled with water at all times. The fish is guided into a sorting chamber through an ejector wherein the smallest fishes fall through a grid and out through an outlet into a net cage while the larger famed fished are send through outlet into another net cage.

FR 974980 A discloses a device for sorting fish depending on their size, where the fishes are all elongated and of the same type. Hence, the same point of reference (e.g. end of the head of the fishes) is chosen for all the fishes. Before separation, the fishes are arranged in the same direction on a table comprising an opening such that the fishes of a certain size will tilt across its point of gravity and thereby fall into the opening. Fishes that do not fall through the opening are guided over the opening onto a conveyor conveying them to a new opening with the same principle as the first opening.

JP 2001304946 A and DK 1214156 T3 disclose devices for sorting different articles, including fish wherein the articles are conveyed on a conveyor, and wherein the articles are oriented in a specific direction when distributed on a distribution conveyor belt having latitudinal gutters wherein fishes of a certain size will be collected and guided therefrom.

None of the mentioned prior art documents disclose a device for sorting out cleaner fish from farmed fish that is efficient and harmless to the fishes.

It is thus an object of the present invention to separate cleaner fish from farmed fish efficiently.

Another object of the present invention is to separate cleaner fish from farmed fish such that the fishes are not harmed during the process.

Summary of the invention

The present invention is set forth and characterized in the independent claims, while the dependent claims describe further characteristics of the invention.

In particular, the present invention concerns a device/separator for separating cleaner fish from farmed fish in the aquaculture industry. The separator can be used to separate cleaner fish in systems where the cleaner fish is transported in fluidbearing lines together with farmed fish.

The separator according to the present invention comprises an inlet tube, a first guiding structure and a first gutter.

The inlet tube guides a flow of transport fluid and fish to be separated into the separator.

The first guiding structure is extending a length L downstream from the inlet tube in a direction equal to the flow direction of the transport fluid exiting from the crosssectional center of the inlet tube, hereinafter called the initial direction. The first guiding structure comprises a first section and a second section. The second section is arranged downstream the first section and comprises a first transport fluid drainage outlet having a maximum opening size inhibiting fish from passing therethrough. The second section may be arranged adjacent the first section.

The first gutter is arranged transverse the direction of the length L of the first guiding structure, and a majority of the cleaner fish is collected therein when exiting downstream of the second section. The first gutter is preferably arranged adjacent the second section for efficient collection of cleaner fish.

The term “downstream of” should be interpreted as downstream of an object in the direction of the length of the first guiding structure, i.e. the downstream of an object along the initial direction.

The term “majority” should be interpreted as an amount of more than 50% of the total amount, preferably more than 70%, even more preferably more than 90%, for example all or near all.

The term “fish” should be interpreted to include cleaner fish and farmed fish, while “farmed fish” should be interpreted as fish subjected to farming such as salmon and trout and “cleaner fish” should be interpreted as fish eating lice from farmed fish such as lump fish or different species of wrasse such as goldsinny or ballan wrasse.

The term “transport fluid” should be interpreted as any fluid allowing transport of fish, for example sea water.

The term “fluid flow” should be interpreted as the flow of transportation fluid which may comprise fish before passing through the drainage outlet.

The separator further comprises a farmed fish outlet tube arranged downstream the first gutter. The outlet tube is configured to guide the farmed fish to an external location for further handling. The first outlet tube may be arranged adjacent the first gutter.

During operation of the separator, the transport fluid enters the fluid inlet tube together with the fish to be separated. The flow of transport fluid and fish is guided onto the first section of the first guiding structure and guided thereon in a direction being parallel to the direction of the length L of the first guiding structure.

The inlet tube may be funnel shaped at its end such that the diameter of the inlet tube increases in the direction of the flow of the transport fluid and fish. In such an embodiment the inlet tube is having its maximum opening size adjacent the first section. Such funnel shaped configuration of the inlet tube contributes to spread the fish onto the first section of first guiding structure.

Further, the farmed fish outlet tube may also be funnel shaped having its maximum opening facing the first gutter.

The first section of the first guiding structure may be a transport structure or transport plate for transporting the flow of transport fluid and the fish to be separated to the second section.

The width of the first section may correspond to the width of the opening size of the inlet tube, where the width is measured orthogonal to the direction of the length L of the first guiding structure. Further, the width of the first section may correspond to the width of the second section of the first guiding structure.

In one embodiment the funnel shaped inlet tube has a rectangular opening adjacent the first section wherein the width of the rectangular opening corresponds to the width of the first section. The height of the rectangular opening may preferably be smaller than the width for contributing to spread of the fish along the width of the first guiding structure. The other end of the inlet tube may have a rectangular, oval or circular opening.

During operation of the separator the flow of transport fluid and fish are guided from the first section to the second section. The second section comprises a fluid drainage outlet where the transport fluid drops such that the direction of the flow of transport fluid changes from the direction of length L of the first guiding structure to a flow having a directional component perpendicular to the direction of length L. Such a change in the direction of the flow of transport fluid creates a downward directed force on the flow which affects the cleaner fish to fall into the first gutter arranged adjacent the drainage outlet of the second section.

The drainage outlet may comprise a two-dimensional grid structure. In a preferred embodiment the drainage outlet comprises grill of longitudinal parallel bars, wherein the distance between the bars is set such that transport fluid may flow relatively freely, but fishes are inhibited from passing through. The grill can be made of metal such as stainless steel or any other material resistant to corrosion in an environment of sea water. The bars may be arranged in a direction parallel to direction of the length L of the guiding structure guiding the fish in the direction towards the first gutter. The bars may further be made of or coated by a material that allows the fish to slide along the initial direction of the flow.

The distance between the bars may for example be from 8 to 10 mm if the cleaner fish is of type lump fish.

The first drainage outlet is preferably arranged along the entire width of the second section, and preferably also arranged along the entire length of the second section.

In an embodiment of the invention the first section comprises a guiding device configured such that a longitudinal length of the farmed fish is orientated parallel to the direction of the length L of the first guiding structure, thereby removing, or at least substantially reducing, the risk of farmed fish falling into the first gutter. Such an embodiment allows the farmed fish to move across and not into the first gutter.

The guiding device may be a fin having a length oriented along the direction of the length of the first guiding structure. It may for example extend from 50 to 100% of a length L1 of the first section of the first guiding structure, or preferably from 80 to 100%, or more preferably from 90 to 100%.

In an embodiment of the invention the first gutter extends over an entire width of the second section.

In the separator according to the invention the first section may comprise a second drainage outlet for transport fluid, preferably arranged adjacent the first drainage outlet. The second drainage outlet may have the same configuration as the first drainage outlet having a maximum opening size inhibiting fish from passing therethrough.

Further, an adjustable fluid restrictor can be arranged below the second drainage outlet preventing the transport fluid from passing therethrough. The adjustable fluid restrictor may extend over an entire width of the second drainage outlet and may further be configured to be displaceable in the direction of length L of the first guiding structure. The effect of such a fluid restrictor is that the size of the second drainage outlet becomes adjustable. This may be necessary in order to avoid that a majority of the transport fluid is flowing into the first gutter.

How large percentage of the transport fluid flow that will surpass the fluid restrictors during operation will inter alia depend on the speed of the transport fluid entering the separator. Thus, the adjustable fluid restrictor may be arranged below the entire length L1 and width of the first section, thereby preventing the transport fluid from passing therethrough. In such an embodiment the second drainage outlet may cover the entire first section. Further, the second fluid drainage outlet may have the same configuration as the first drainage outlet, being a two-dimensional grid structure or preferably a grill of longitudinal parallel bars.

The fluid restrictor may be sliding within a casing mounted below a part of the first section void of the second transport fluid drainage outlet and/or at the side of the first section and/or above the first section.

The fluid restrictor may for example be moved manually or automatically by a hydraulic or pneumatic cylinder. Further, the movement can be remotely operated.

Further, a sensor may be arranged at the first gutter and/or at the first drainage outlet sensing the fall of transport fluid through the first drainage outlet, thereby allowing adjustment of the size of the second drainage outlet to regulate the spill of fluid into the first gutter. The sensor may comprise a transmitter transmitting the signals to a receiver for monitoring the operation.

Further, a camera can be installed for observing the separator during operation.

The separator may further comprise at least one first fluid injector arranged above the first guiding structure to inject fluid towards the first guiding structure and having a directional component in the direction of length L of the first guiding structure such that, during operation, the fish present on the first guiding structure will be forced to move in the direction of length L of the first guiding structure.

The first fluid injector may comprise a fluid pipe extending in the direction of the width of the first guiding structure having at least one nozzle, preferably a plurality of nozzles, injecting fluid. The nozzles are preferably evenly distributed along the length of the pipe.

A plurality of such pipes can be distributed above the first guiding structure.

The separator may further comprise at least one second fluid injector arranged to inject fluid into the first gutter in a direction transverse the direction of length L of the first guiding structure, thereby forcing the cleaner fish out of the separator during operation.

In an embodiment, the separator may further comprise a second guiding structure having a length L’. The second guiding structure being arranged downstream the first gutter. Further, the second guiding structure may be arranged adjacent the first gutter. Further, a second gutter may be arranged downstream the second guiding structure and preferably adjacent the second guiding structure. This is an advantageous embodiment since it will ensure that any amount of cleaner fish not collected in the first gutter is transported onto the second guiding structure for further separation. For example, the uncollected cleaner fish can be transported along the second guiding structure into the second gutter which is oriented parallel with the first gutter.

It should be understood that a plurality a of guiding structures and gutters can be arranged downstream the first gutter in an alternating sequence as shown for the second guiding structure and second gutter.

The second guiding structure may comprise a grill of longitudinal parallel bars arranged parallel the direction of the length L’ of the second guiding structure for guiding the fish in the same direction. The distance between the bars of the grill is adjusted such that the second guiding structure prevents transport fluid and fish from passing therethrough.

Further, a third fluid injector can be arranged above the second guiding structure forcing the cleaner fish to move towards the second gutter. Such a third fluid injection may be similar to the first fluid injector.

The separator may further comprise at least one fourth fluid injector arranged to inject fluid into the second gutter in a direction transverse the direction of length L’ of the second guiding structure, thereby forcing the cleaner fish out of the separator during operation.

It should be understood that a plurality a of guiding structures and gutters can be arranged downstream the first gutter in an alternating sequence as shown for the second guiding structure and second gutter. Further, a plurality of fluid injectors can be arranged in connection with the plurality of guiding structures and gutters to force the cleaner fish to move in a determined direction.

The present invention also involves a method for separating cleaner fish from farmed fish in a separator according to any of the features mentioned above. The method comprises the following sequential steps:

a) starting a flow of transport fluid into the inlet tube,

b) guiding the flow of transport fluid from the inlet tube onto the first guiding structure and through the drainage outlet of the second section, thereby changing the direction of the flow of transport fluid from the initial direction to a flow having a directional component perpendicular to the initial direction.

c) guiding the fishes to be separated into the inlet tube,

d) regulating or maintaining the flow of transport fluid such that the fishes are transported through the inlet tube and onto the first guiding structure,

and

d) collecting cleaner fish in the first gutter.

The method may further comprise the step of:

e) collecting the farmed fish at an outlet tube arranged adjacent and downstream the first gutter.

Further, as mentioned above, a minority of the cleaner fish may not be collected in the first gutter. If the separator further comprises a second guiding structure, the uncollected cleaner fish will be guided onto the second guiding structure and collected in a second gutter arranged downstream the second guiding structure. From the second gutter, the cleaner fish will be guided out of the separator.

Brief description of the drawings

Fig. 1 is a cross-sectional side-view of a separator according to an exemplary embodiment of the present invention;

Fig. 2a and 2b are cross-sectional side-views of a separator according to an exemplary embodiment of the present invention;

Fig. 3 is a cross-sectional side-view of a separator according to an exemplary embodiment of the present invention;

Fig. 4 is a perspective view of a separator according to an exemplary embodiment of the present invention;

Fig. 5 is view of a separator according to an exemplary embodiment of the present invention seen perpendicularly from above;

Fig. 6 is a close-up view of area A in fig. 5.

In the drawings, like reference numerals have been used to indicate like parts, elements or features unless otherwise explicitly stated or implicitly understood form the context.

Detailed description of the invention

In the following, embodiments of the invention will be discussed in more detail with reference to the appending drawings. It should be understood, however, that the drawings are not intended to limit the invention to the subject-matter depicted in the drawings.

Fig. 1 shows an exemplary embodiment of the separator of the invention. The funnel shaped inlet tube 6 is arranged at a first end of the separator. The flow F of transport fluid 10 and fish 2,3 and is guided through the inlet tube 6 towards the first guiding structure 13 which is divided in a first and second section 13a,13b.

The guiding structure 13 is extending in a length L (see Fig. 2b) downstream the inlet tube 6 and is having a direction which corresponds to the initial direction of the flow F of the transport fluid 10 when exiting from the inlet tube 6.

The first section 13a arranged adjacent to the inlet tube 6, and a second section 13b arranged downstream and adjacent the first section 13a.

The first section 13a guides the flow F of transport fluid 10 and fish 2,3 towards the second section 13b. Further, the longitudinal length of the farmed fish 2 is orientated parallel to the direction of length L of the first guiding structure 13 by the guiding device 4 arranged on the first section 13a. The guiding device is a fin having a length oriented parallel to the direction of the of length L of the first guiding structure 13.

The second section 13b has a drainage outlet 11 wherein the transport fluid 10 passes through but not the fish 2,3. The second section 13b has a grill structure of longitudinal bars orientated parallel with the direction of the length L but being spaced apart from each other allowing the transport fluid to pass through the openings created between the bars. See Fig. 6 for details.

When the transport fluid 10 passes through the drainage outlet 11, the cleaner fish 3 is guided into and collected at the first gutter 12. The farmed fish is guided across the top of the first gutter 12 and into an outlet tube 1 (partly shown) arranged adjacent and downstream the first gutter 12.

Above the first guiding structure 13 a plurality of first fluid injectors 5 are arranged to inject fluid towards the first guiding structure 13 such that, during operation, the fish 2,3 present on the first guiding structure 13 will be forced to move in the direction of length L of the first guiding structure 13.

Fig. 2a discloses nearly all the features of the separator in Fig. 1, the difference being that the first section 13a of the first guiding structure 13 in Fig. 2a comprises a second drainage outlet 18 such that the total drainage outlet area of the first guiding structure 13 can be larger than the area of the first drainage outlet 11. The size of the area of the second drainage outlet 18 can be adjusted by arranging the fluid restrictor 9 below the first section 13a. In the embodiment shown in Fig. 2a, the fluid restrictor 9 extends in under the entire area of the first section 13a, i.e. covering the area in the length and width direction thereof.

The first section 13a has, as described for the second section 13b, a grill structure of spaced apart parallel longitudinal bars.

The fluid restrictor 9 is movable/sliding in the direction parallel with the length L of the first guiding structure 13 indicated by double arrows in Fig. 2a. When the fluid restrictor 9 is arranged below the entire area of the first section 13a transport fluid 10 and fishes 2,3 are inhibited from passing therethrough. In this embodiment, the first guiding structure comprises only one drainage outlet, being the first drainage outlet 11. When the fluid restrictor 9 is slid away from an area underneath the first section 13a, the second drainage outlet 18 is created allowing only the transport fluid 10 to pass through that area and not the fishes 2,3.

The fluid restrictor 9 is sliding within the casing 8 arranged below a part of the first section 13a void of the second drainage outlet 18, i.e. the casing 8 is arranged such that is does not block the second drainage outlet 18. The casing 8 is fixed to the separator below the first section 13a by supporting means 7.

To increase the area of the opening of the second drainage outlet 18, the fluid restrictor 9 is slid in the direction towards the inlet tube 6. The longer the distance the fluid restrictor 9 is slid in that direction, the bigger opening area of the second drainage outlet 18 is provided.

Depending on inter alia the speed of the flow of transport fluid 10, the total area of the drainage outlet 18 can be adjusted to avoid that a majority of the transport fluid 10 is flowing into the first gutter 12, which would lead to a non-working or inefficient separation of cleaner fish from farmed fish.

Fig. 2b shows the same embodiment as Fig. 2a indicating the direction and length L of the first guiding structure 13, the length L1 of the first section 13a and length L2 of the second section 13b. The length L2 of the second section is shorter than the length L1 of the first section 13a.

Further, the width W of the second guiding structure is indicated by a white line having a length corresponding to the width of the first guiding structure.

The direction of the length L of the first guiding structure is equal to the direction of the lengths L1, L2 of the first and second section 13a,13b respectively.

The dimensions of the width and length L1 of the first section 13a will depend on the speed of the flow of transport fluid 10 and pumping capacity of the farmed fish 2 into the separator.

The dimensions of the width and length L2 of the second section 13b will also depend on the flow of transport fluid 10 and pumping capacity of the farmed fish 2 into the separator to ensure that a majority of the transport fluid passes through the first drainage outlet which’s area can be expanded to include the second drainage outlet 18 when arranged adjacent the first drainage outlet 11.

Fig. 3 to 5 show a further exemplary embodiment of the separator of the invention where the separator further comprises a second guiding structure 16 and a second gutter 14.

The second guiding structure 16 is arranged downstream and adjacent the first gutter 12 and extends as shown in Fig. 5 in a length L’.

Fig. 3 further shows two third fluid injectors 19 arranged on top of the second guiding element 16 for injecting fluid which forces the cleaner fish to move towards the second gutter 14. Thus, cleaner fish 3 not collected in the first gutter 12 travel along the second guiding structure 16 by the aid of injected fluid from the third fluid injectors 19 and into the second gutter 14.

Fig. 3 and 4 further show that the second guiding structure 16 has guiding devices 4 arranged thereon ensuring the that the longitudinal length of the farmed fish 2 is orientated parallel to the direction of length L’ of the second guiding structure 16 avoiding farmed fish 2 from falling into the second gutter 14.

Fig. 5 further indicate second and fourth fluid injectors 15,20 arranged to inject fluid into the first and second gutter 12,14 respectively, where the direction of the injected fluid is transverse the direction of length L, L’ of the first and second guiding structure respectively. The fluid from the second and fourth fluid injectors 15,20 forcing the cleaner fish out of the first and second gutter 12,14 respectively during operation of the separator.

Fig. 6 is a close-up view of the area A indicated in Fig. 5 and shows a part of the grill of the first guiding structure showing the longitudinal parallel bars 17, wherein the distance between the bars 17 is set such that transport fluid may flow relatively freely, but fishes are inhibited from passing through.

List of reference numerals / letters

1 Farmed fish outlet

2 Farmed fish

3 Cleaner fish

4 Guiding device

5 First fluid injector

6 Inlet tube

7 Supporting means

8 Casing

9 Fluid restrictor

10 Transport fluid

11 First drainage outlet

12 First gutter

13 First guiding structure

13a First section of first guiding structure

13b Second section of first guiding structure

14 Second gutter

15 Second fluid injector

16 Second guiding structure

17 Parallel longitudinal bars

18 Second drainage outlet

19 Third fluid injector

20 Fourth fluid injector

F Flow of transport fluid

L Length of first guiding structure

L’ Length of second guiding structure

L1 Length of first section of first guiding structure L2 Length of second section of first guiding structure W Width of the first and second guiding structure

Claims

1. A separator for separating cleaner fish (3) from farmed fish (2),

comprising

- an inlet tube (6) for guiding a flow (F) of transport fluid (10) and fish (2,3) to be separated,

characterized in that the separator further comprises

- a first guiding structure (13) extending a length L downstream from the inlet tube (6), the first guiding structure comprising a first section (13a) and a second section (13b) arranged downstream the first section (13a), wherein the second section (13b) comprises a first transport fluid drainage outlet (11) having a maximum opening size inhibiting fish (2,3) from passing therethrough,

- a first gutter (12) arranged transverse a direction of length L of the guiding structure (13) for collecting a majority of the cleaner fish (3) exiting downstream of the second section (13b), and

- a farmed fish outlet tube (1) arranged downstream the first gutter (12) and configured to guide the farmed fish (2) to an external location for further handling.

2. The separator according to claim 1, characterized in that the inlet tube (6) is funnel shaped having its maximum opening size adjacent the first section (13a).

3. The separator according to claim 1 or 2, characterized in that the farmed fish outlet tube (1) is funnel shaped having its maximum opening facing the first gutter (12).

4. The separator according to any one of the preceding claims, characterized in that the first section (13a) comprises a guiding device (4) configured such that a longitudinal length of the farmed fish is orientated parallel to the direction of length L.

5. The separator according to claim 4, characterized in that guiding device (4) is a fin having a length oriented along the direction of the direction of length L.

6. The separator according to any one of the preceding claims, characterized in that the first gutter (12) extends over an entire width of the second section (13b).

7. The separator according to any one of the preceding claims,

characterized in that the first section (13a) comprises a second transport fluid drainage outlet (18) arranged adjacent the first drainage outlet (11), the second transport fluid drainage outlet (18) having a maximum opening size inhibiting fish (2,3) from passing therethrough, and

wherein an adjustable fluid restrictor (9) is arranged below the second drainage outlet (18) preventing the transport fluid (10) from passing therethrough.

8. The separator according to claim 7, characterized in that the adjustable fluid restrictor (9) extends over an entire width of the second drainage outlet (18).

9. The separator according to claim 7 or 8, characterized in that the adjustable fluid restrictor (9) is configured to be displaced in the direction of length L.

10. The separator according to any one of the preceding claims, characterized in that the separator further comprises at least one first fluid injector (5) arranged above the first guiding structure (13) to inject fluid towards the guiding structure and having a directional component in the direction of length L such that, during operation, the fish (2,3) present on the first guiding structure (13) will be forced to move in the direction of length L.

11. The separator according to any one of the preceding claims, characterized in that the separator further comprises at least one second fluid injector (15) arranged to inject fluid into the first gutter (12) transverse of the direction of length L.

12. The separator according to any one of the preceding claims, characterized in that the separator further comprises

a second guiding structure (16) arranged a length L’ downstream the first gutter (12) and

a second gutter (14) arranged downstream the second guiding structure (16) and

wherein the first and second gutters (12,14) are oriented in parallel.

13. A method for separating cleaner fish from farmed fish in a separator according to any one of claims 1-12, characterized in that the method comprises the following sequential steps:

a) starting a flow (F) of transport fluid (10) into the inlet tube (6),

b) guiding the flow (F) from the inlet tube (6) onto the guiding structure (13) and through the drainage outlet (11) of the second section (13b),

c) guiding the fishes (2,3) to be separated into the inlet tube (6),

d) regulating or maintaining the flow (F) of transport fluid (10) such that the fishes (2,3) are transported through the inlet tube (6) and onto the guiding structure (13), and

e) collecting cleaner fish (3) in the first gutter (12).

14. The method according to claim 13, characterized in that the method further comprises the step of:

f) collecting the farmed fish (2) at an outlet tube (1) arranged adjacent and downstream the first gutter (12).